1. Field of the Invention
This invention relates to a novel and improved scintillation crystal device. It also relates to a novel and improved scintillation camera incorporating such crystal device. Generally speaking, this invention relates to the field of nuclear medicine.
2. Description of the Prior Art
The trends in modern nuclear medicine go towards the use of new radionuclides, radiopharmaceuticals and imaging techniques (such as with 81 m-Kr, 111-In, 195 m-Au, 75-Se, 67-Ga, 131-I--labelled antibodies), "first pass" cardiology studies, planar studies with positron emitters, single photon emission computerized tomography (SPECT), and positron emission tomography (PET). The contemporary single crystal scintillation cameras (SCs) of the Anger type (see e.g. U.S. Pat. No. 3,011,057 to Anger) with reduced crystal thickness, due to improvements made in the domain of distortion correction, as far as linearity and uniformity are concerned (see e.g. U.S. Pat. No. 3,745,345 to Muehllehner and U.S. Pat. No. 4,298,944 to Stoub et al.) achieve fine intrinsic spatial resolution. They are quite acceptable for static and slow-dynamic planar imaging with low energy single photon emitting tracers having energies up to 140 KeV (such as 133-Xe, 201-Tl, and the most widespread one, 99 m-Tc). However, their potentials in "first pass" nuclear cardiology studies, in efficient detection of the above listed medium energy gamma emitting radionuclides, as well as in SPECT with rotating SC heads and detection of positron emitters (planar and tomographic with dual head cameras) are limited. Recently, this problem was addressed in an article entitled "Improved Intrinsic Resolution: Does It Make a Difference?" by Hoffer et al. in J. Nucl. Med. 25, 230 (1984).
Multi-crystal cameras (MCs) (see e.g. Bender and Blau: "The Autofluoroscope"; Nucleonics 21, 10, 52 (1963)) are sensitive enough and, therefore, advantageous for high counting rate dynamic studies and efficient detection of medium and high energy photons. The disadvantage of MCs is that they have poor spatial and energy resolution.
Collimators of various configurations for scintillation cameras are disclosed in U.S. Pat. Nos. 3,921,000, 3,943,366 and 4,057,726, which are incorporated herein by reference.